Abstract: A respiratory humidification system having a capillary passage in communication with a ventilator, the ventilator adapted to deliver an air stream, a heater operable to at least partially vaporize water in the capillary passage, a pumping unit adapted to supply water to the capillary passage, wherein the water upon heating is at least partially vaporized to form an aerosol stream. The aerosol stream is combined with the air stream to form a humidified air stream.

Abstract: A system and method for closed-loop testing of a biological or chemical sensor is disclosed. The tester is fluidically coupled to the input port and exhaust port of a sensor. A mixture of a chemical or biological simulant and air is generated by the tester and is delivered to the sensor. The mixture of simulant and air exiting the sensor is delivered to a collection device.

Abstract: Apparatuses, methods and systems directed to reducing mineral buildup on drift eliminators of a cooling tower. Some embodiments of the invention allow irrigation of the drift eliminators of the cooling tower with fluid in the basin of the cooling tower to reduce mineral buildup. In other embodiments, the systems disclosed can be integrated with the drift eliminators to provide constant irrigation of to reduce mineral buildup. In some other embodiments, a control unit is used to selectively irrigate the drift eliminators based on the fluid temperature in the basin and the temperature inside and outside of the cooling tower.

Abstract: A system and method for carbonizing a liquid, such as tap water with CO2, are disclosed. The liquid is carbonized inside a pump housing, thereby obviating the need for a separate high-pressure carbonator tank and a separate feed pump. The pump housing has an inlet for receiving in combination the liquid and CO2 at a first pressure, and an outlet for transporting the liquid carbonized with CO2 from the pump housing into an outlet line at a second pressure higher than the first pressure. A constriction is disposed in the outlet line for producing said higher pressure with the pump. The system and method can be employed in closed-loop carbonizing systems in the beverage industry.

Abstract: An object is to provide a micro-bubble generator, etc., capable of efficiently generating bubbles having a particle size of a nanometer order. One aspect of the present invention is a micro-bubble generator provided with a swirl chamber, a fluid introduction opening connected to the swirl chamber, the fluid introduction opening for introducing fluid along a line tangent to an inner surface of the swirl chamber, and a discharge tube for guiding the fluid in the direction substantially perpendicular to the direction in which the fluid is introduced. The discharge tube penetrates a wall surface of the swirl chamber and protrudes to an interior of the swirl chamber. According to the present configuration, by isolating a path of the introduced fluid, a loss of kinetic energy of a swirl flow of the fluid can be reduced. Thus, the micro-bubble generator capable of reducing the size of the generated micro-bubbles can be obtained.

Abstract: An intake pipe is positionable adjacent to the bottom of a body of water. The intake pipe has at least one perforate section adapted to receive stagnating un-aerated water. A discharge pipe is positionable between a waterline of the body of water and the discharge pipe. The discharge pipe has at least one orifice for injecting aerated water into the body of water. An intermediate pipe section has an input end coupled to the discharge pipe. The intermediate pipe section has an output end coupled to the discharge pipe. A pump moves water from the perforate section of the intake pipe to the orifice of the discharge pipe. A venturi assembly injects air into water flowing to and through and out of the discharge pipe into the body of water.

Abstract: An aqueous scream is pumped through a vortex cylinder. The aqueous stream is rotated in a downwardly moving spiral stream within the vortex cylinder at a high downward velocity. The downward velocity of the aqueous stream increases as it flows through a discharge conduit concentrically located within a mixing chamber of the vortex cylinder. An adjustable air inlet tube open to atmospheric pressure extends through the vortex chamber and into the discharge conduit. A negative pressure zone is created at the discharge end of the discharge conduit for drawing air into the aqueous stream for mixing therewith and dissolving oxygen in the aqueous solution.

Abstract: A wastewater treatment system having a tank, a rotatable surface aerator and an elongate draft tube is presented. The elongate draft tube is at least partially submerged beneath the liquid and is rotated about its longitudinal axis for orbitally moving the liquid through the tank in a fixed direction. The rotatable surface aerator is coupled to the proximal end of the draft tube and is at least partially immersible into the liquid. The system further can provide an anoxic zone. A process for treating wastewater is also provided.

Abstract: Provided is a system for dissolving gas into liquid contained within a body. The system may include a tubular body extending between a bottom end and a top end, a gas diffuser coupleable to a gas source and configured for discharging gas bubbles into the tubular body, and a liquid pump for propelling liquid within the tubular body in a downwards direction, against uprising gas bubbles, where the liquid egresses at the bottom end of the tubular body.

Abstract: A humidity control device is for controlling the humidity of air in a target space, and the humidity control device comprises: a processor for controlling the humidity of air in the target space by passing air through a hygroscopic liquid L; a regenerator for regenerating the hygroscopic liquid L used for the process by the processor; a hygroscopic-liquid pipe path (50), provided so as to pass through a ventilation opening (70) intended for ventilating the target space, for transferring the hygroscopic liquid L from the processor to the regenerator; and a discharged-air-utilizing regeneration unit (60) for regenerating the hygroscopic liquid L by passing air to be discharged from the target space through the ventilation opening (70) through the hygroscopic liquid L flowing through the hygroscopic-liquid pipe path (50) toward the regenerator. A humidity control device whose energy utilization efficiency is improved is thus provided.

Abstract: The invention relates to an apparatus for the treatment of gaseous effluents, such as those originating from the production of semi-conductors involving contact with a liquid. The inventive apparatus consists of: a gas/liquid contact chamber which can receive a liquid in the lower part thereof and which is topped with a gas cover, said chamber comprising means for introducing a gas to be treated and means for releasing residual gases following treatment involving contact with the liquid; turbine-type gas/liquid contacting means comprising one or more stages which ensure improved contact between the gas and the liquid, the upper part of said means being equipped with an opening for drawing the gas situated in the gas cover above the liquid; and, preferably, means for measuring the pH of the liquid.

Abstract: A housing containing a reservoir can be mounted to receive water from an outlet port of a humidifier system. A pump having a pump inlet hydraulically connected to the reservoir volume and a pump outlet adapted to connect to an inlet port on the humidifier system can be controlled to deliver water to the humidifier based on a control signal received at a processor. The reservoir can be flushed based on one or more of an elapsed operating time since the last flush and a total time since the last flush. Flushing can be performed using a re-fill port adapted to receive fresh water from an external water source and draining process that can include creating a siphoning action that causes the water to drain from the reservoir volume. Flow of fresh water into the re-fill port can also be controlled to maintain a proper working water level in the reservoir volume. Related systems, apparatus, methods, and/or articles are also described.

Abstract: Dry pond water evaporation systems and methods are used to evaporate large quantities of water from industrial waste water sources, such as water produced by oil and gas wells. Dry pond systems include a water evaporation system that emits waste water into the air as a fine spray or mist to promote evaporation. Water that falls to the ground and any initially dissolved solids are captured in a water capture depression. Water and solids are transferred from the water capture depression to a water collection pool. Water from the water collection pool is recirculated through the water evaporation system to further concentrate the total dissolved solids (TDS). When the TDS are sufficiently concentrated, they may be harvested, such as by evaporating off the water and recovering salts or minerals as a solid.

Abstract: A liquid displacement system includes a storage tank, a volume of a first gas, and a volume of a second gas. The storage tank has at least one water ballast compartment to store water and at least one liquid storage compartment to store liquid and is configured symmetrically. A pump module may also be coupled to the storage tank. The pump module has at least one pair of loading pumps operating substantially at equal mass flow rate to displace the water with the liquid, and at least one pair of offloading pumps operating substantially at equal mass flow rate to displace the liquid with the water. Also, a gas valve module may be coupled to the storage tank to control pressure of the first gas and the second gas in the storage tank. The first gas is natural gas or inert gas. The second gas is natural gas.

Abstract: A system and method for managing water content in a fluid include a collection chamber for collecting water from the fluid with a desiccant, and a regeneration chamber for collecting water from the desiccant and transferring it to a second fluid. An evaporator cools the desiccant entering the collection chamber, and a condenser heats the desiccant entering the regeneration chamber. Diluted desiccant from the collection chamber is exchanged with concentrated desiccant from the regeneration chamber in such a way as to efficiently control the transfer of both mass and heat between the chambers. In one embodiment, mass is not exchanged until one or both of the desiccant levels in the chambers exceeds a predetermined level. Heat is transferred between the two desiccant flows as they are transferred between the chambers. This increases efficiency and reduces the energy input required for the evaporator and the condenser.

Abstract: An evaporative cooler for cooling air includes a cooling housing having an air inlet and an air outlet and an evaporation media, located within the cooling housing intermediate the air inlet and the air outlet for air flow there through and for receiving water to permit evaporation of at least some water. The evaporative cooler includes a drain pan located within the cooling housing and below the evaporation media to catch water which has not evaporated and falling from the evaporation media and a sump located within the cooling housing and below the drain pan for collecting water for use in supplying water to the evaporation media. The evaporative cooler includes a pipe connecting the drain pan to the sump for water movement from the drain pan to the sump and an air vent located within the cooling housing and connected to the pipe, the air vent being open to air within the cooling housing and above the drain pan to permit release of air from within the pipe.

Abstract: A microbubble generator (20) includes an outer cylinder (201), bulkhead (202) and an inner cylinder (203) extending in the downstream direction from the bulkhead (202). A plurality of liquid passage holes (202a) is formed in the central portion of the bulkhead (202), and a circumferential flange (203a) is formed at the downstream end of the inner cylinder (203). A disk (204) is disposed adjacent to the rear edge of the inner cylinder (203). The disk (204) and circumferential flange (203a) define a restriction passage (17) in conjunction with each other. The circumferential flange (203a) forming one of the wall surfaces of the restriction passage (17) has a recess (206) formed therein.

Abstract: A microscopic bubble generating apparatus includes a Roots-type pump including a pair of multi-lobed Roots rotors housed in a pump casing, and a drive motor rotating the rotors, a suction pipe connected to a suction port of the pump casing, a discharge pipe connected to a discharge port of the pump casing, and a conduit communicating with the suction pipe and having an air inlet and a collision member with which sucked water is caused to collide. The pump is operated to suck water through the suction pipe and to cause the water mixed with air sucked through the air inlet to collide with the collision member so that a number of bubbles are generated. The bubbles are refined by a compressing action of the pump to be rendered microscopic. The water containing the microscopic bubbles is released from the discharge pipe into water in a septic tank or river.

Abstract: A method and apparatus for treating a fluid is provided and includes a fluid storage tank for partially containing a fluid and a gas, wherein the fluid storage tank includes a fluid inlet pipe and a fluid outlet pipe. The fluid treatment apparatus also includes a first aeration device, wherein the first aeration device is configured to be in flow communication with the fluid inlet pipe and the fluid portion of the tank cavity. The fluid treatment apparatus further includes a pumping device, wherein the pumping device is configured to cause the fluid portion of the tank cavity to flow through the fluid outlet pipe and a second aeration device, wherein the second aeration device is configured to be in flow communication with the fluid outlet pipe and the fluid portion of the tank cavity.

Abstract: Systems and methods for lowering levels of carbon dioxide and other atmospheric pollutants are provided. Economically viable systems and processes capable of removing vast quantities of carbon dioxide and other atmospheric pollutants from gaseous waste streams and sequestering them in storage-stable forms are also discussed.

Abstract: The invention relates to a device for supplying gas into water in sea cages, tanks or ponds with a pump and a dissolver for contacting the gas with the water. For higher efficiency and better handling the pump is a submerged pump.

Abstract: The invention relates to a device which can be used to aerate a body of liquid such as wine. The device is provided to be portable and to be used with a body of liquid which is held within a container from which the liquid can be directly consumed.

Abstract: During a method for the production of milk foam or milk-based drinks, milk is sucked with a pump (1) out of a container (3, 3?) and conveyed to an outlet (11?), wherein air and/or a gas is added to the milk. The milk/air mixture is processed in a cold state into milk foam and conveyed as cold milk foam to the outlet (11?).

Abstract: A contact body for an evaporation humidifier or material exchanger, is formed of corrugated material layers. The novel contact body has material layers which are a thermoplastic plastic and are interconnected by welding and/or bonding and or a positive fit. The corrugation axes at two longitudinal edges of each material layer form a corrugation axis section that runs approximately in an orthogonal direction in relation to the respective longitudinal edge and the axes between the corrugation axis sections have oblique regions that run in at least two different directions with at least one change of direction in between, in such a way that in each material layer the corrugation axes change direction at least three times. The corrugation axes in a first oblique area lie at an angle ?1 to the neighboring longitudinal edge and in a second oblique area lie at an angle ?2 to the other longitudinal edge. The angles ?1 and ?2 are between 30° and 60°. The maximum height of the corrugated material layers is 12 mm.

Abstract: A process for producing carbonated water having a high concentration, inexpensively and easily, involves using a static mixer having 20 to 100 elements so as to provide a value Re×N of 100,000 to 2,000,000, in with Re represents a Reynolds number, when a mixture of water and carbonic acid gas flow in the static mixer.

Abstract: The present invention is a biogas processing system having a compressor having a biogas input and output, a pump having a water input and output, a scrubber tower having a mixing chamber connected to a biogas input, a water pump input, a water output, and a processed biogas output, and a filtration member connected to the water output to remove contaminants from the water exiting the first scrubber tower. The system also includes devices for heating and cooling the recycled flow of water to enhance the ability of the water to absorb contaminants from the biogas and the ability of a stripper to remove absorbed contaminants from the water in a closed loop water system, and a controller for closely controlling the operating parameters of the system to achieve safe an optimal operation of the system.

Abstract: A tube in one embodiment is formed with a non-stick coating on its inner outer surface. Preferably, the non-stick coating is fluoropolymer. More preferably the fluoropolymer is PTFE. Another non-stick coating is formed on an inner surface of the tube in another embodiment. The non-stick coating served as a de-fouling layer is capable of preventing impurities in the water flowing through the tubes from precipitating thereonto. Hence, the performance of a cooling tower incorporating the tubes can be increased significantly.

Abstract: This invention concerns an apparatus and a method for producing carbonated water capable of obtaining high concentration carbonated water effectively. Carbon dioxide gas is passed through a first carbon dioxide gas dissolver composed of a membrane module to be dissolved in water and the carbonated water passing through the first carbon dioxide gas dissolver is passed through a static mixer, which is a second carbon dioxide gas dissolver. Consequently, a high concentration carbonated water can be obtained remarkably, effectively and easily with a simpler structure than conventionally.

Abstract: An ozonation system may include a mixing chamber having an inlet to a recirculation conduit within the chamber and proximate to its top, a recirculation conduit for withdrawing fluid from the mixing chamber through the inlet and conducting it to a pump, a venturi connected to the outfeed of the pump for induction of ozone into the water, an infeed for reintroducing a water-ozone mixture back into the chamber, the infeed terminating in a restricting nozzle.

Abstract: A compact, improved injector-mixer for injecting and thoroughly mixing fine bubbles of air into a contaminated water stream from a fish tank is disclosed. Water is pumped down through an injection section of the present invention where air is injected into the stream by an improved Venturi construction. The mixture then flows into an improved mixing section, vertically disposed within a protein skimmer chamber, where it is thoroughly mixed such that the plethora of small air bubbles have a greater chance to bond with the contaminants of the water, the contaminants becoming buoyant as a result. Upon introduction of the mixture into the protein skimmer chamber, the bubbles of air and contaminants attached thereto rise to the top of the protein skimmer column to be contained, while the filtered and oxygenated water is returned to the tank through a base of the protein skimmer chamber.

Abstract: In a gravity fed cooling tower liquid return system having a common header with a plurality of valved sub-headers, a distributive control system, risers on the sub-headers, and sensor/transmitters on the risers, some of the sensor/transmitters controlling the valves on their respective sub-headers, sensing the liquid level in each of the sub-headers, comparing the sensed liquid levels in the distributive control system, and controlling the liquid levels in the sub-headers in response to the sensed liquid levels.

Abstract: The methods and the apparatuses of an aeration equipment are described. A floatable aeration equipment with mobility at least has a floatable apparatus, a plurality of aeration apparatuses, and a controller. The thrust causing the motion of the aeration equipment is generated from the aeration apparatuses while aerating. The moving directions and positions of aeration equipment are controlled by a controller, which switches on/off a power source of one or more selected aeration apparatus.

Abstract: Systems and methods are disclosed herein that provide for liquid waste aeration.

Abstract: A system for aerating liquid within a liquid retention structure including a liquid delivery tube in fluid communication with a gas exchange chamber and a pump. The gas exchange chamber includes an air inlet and a gas outlet. The pump is configured to pump liquid within the liquid retention structure through the liquid delivery tube and into the gas exchange chamber so that harmful gases contained within the liquid escape from the liquid and exit through the gas outlet. Fresh air enters into the gas exchange chamber through the air inlet and is absorbed into the liquid within the gas exchange chamber.

Abstract: A gas-liquid dissolving apparatus includes an intake unit that takes in to-be-treated water from an oxygen-deficient water area, an oxygen-containing gas supply unit, a bottomed gas-liquid dissolving chamber that has at least one hole formed in a lower portion and a top plate provided in an upper portion, a nozzle that ejects the gas supplied by the supplying unit and the water supplied by the intake unit, a gas-liquid separating chamber that has a gas-vent hole formed in an upper portion and a takeout port provided in a lower portion thereof, and a water supplying unit that returns the water taken out from the takeout port to the oxygen-deficient water area.

Abstract: A UV disinfection humidifier has its disinfection properties improved by recirculating the water through the UV treatment unit and/or guiding the water along the UV tube in a helical path.

Abstract: An aqueous scream is pumped through a vortex cylinder. The aqueous stream is rotated in a downwardly moving spiral stream within the vortex cylinder at a high downward velocity. The downward velocity of the aqueous stream increases as it flows through a discharge conduit concentrically located within a mixing chamber of the vortex cylinder. An adjustable air inlet tube open to atmospheric pressure extends through the vortex chamber and into the discharge conduit. A negative pressure zone is created at the discharge end of the discharge conduit for drawing air into the aqueous stream for mixing therewith and dissolving oxygen in the aqueous solution.

Abstract: A water curtain is provided which includes a drape assembly having a drape hood, material drape, float overflow shut-off, collection return, a drainage line solenoid which preferably is electric, a drainage line, a filter, drape solenoid which preferably is electric, a drape feed line, a pump, a pump power line, an on/off switch to a power source which preferably is a ground fault circuit interrupter (GFCI) power line for obvious safety concerns, a feed line, and a shutoff valve. The water supply may be electrically controlled by solenoid valves and has a float overflow shutoff control in some embodiments.

Abstract: This invention concerns an apparatus and a method for producing carbonated water capable of obtaining high concentration carbonated water effectively. Carbon dioxide gas is passed through a first carbon dioxide gas dissolver composed of a membrane module to be dissolved in water and the carbonated water passing through the first carbon dioxide gas dissolver is passed through a static mixer, which is a second carbon dioxide gas dissolver. Consequently, a high concentration carbonated water can be obtained remarkably, effectively and easily with a simpler structure than conventionally.

Abstract: A process for producing carbonated water having a high concentration, inexpensively and easily, involves using a static mixer having 20 to 100 elements so as to provide a value Re×N of 100,000 to 2,000,000, in with Re represents a Reynolds number, when a mixture of water and carbonic acid gas flow in the static mixer.

Abstract: A pressurized water tank having a head space includes a pump for recirculating the water through a nozzle disposed in the head space. The outflowing stream of water will entrain air and cause mixing of air entrained water with the remaining water in the tank. To enhance air entrainment and convey the air entrained water to a location well below the water level, the stream of water is injected into a vertical venturi tube. The entrained air will have an oxidizing effect upon organic matter and also cause circulation of the water within the tank. To enhance oxidation of organic and inorganic matter, a UV lamp may be located in the head space to convert oxygen molecules in the air into ozone molecules. Such ozone molecules would be entrained in the stream of water flowing out of the nozzle and into the tube and have a strong oxidizing effect upon organic and inorganic matter.

Abstract: This invention concerns an apparatus and a method for producing carbonated water capable of obtaining high concentration carbonated water effectively. Carbon dioxide gas is passed through a first carbon dioxide gas dissolver (7) composed of a membrane module to be dissolved in water and the carbonated water passing through the first carbon dioxide gas dissolver (7) is passed through a static mixer (13), which is a second carbon dioxide gas dissolver. Consequently, a high concentration carbonated water can be obtained remarkably, effectively and easily with a simpler structure than conventionally.

Abstract: A carbonic water production apparatus equipped with a carbonic acid gas dissolving apparatus 3 and a circulation pump 1, wherein water in a bath 11 is circulated by the circulation pump 1, and a carbonic acid gas is fed into the carbonic acid gas dissolving apparatus 3 to dissolve the carbonic acid gas in the water. The circulation pump 1 is a positive-displacement metering pump having a self-priming ability. A carbonic water production method using this apparatus is also provided, including an early step for producing carbonic water and a concentration maintaining step for the carbonic water. The carbonic water production apparatus includes a control for controlling the feeding pressure of carbonic water gas to give an intended concentration of carbonic acid gas. The carbonic water production apparatus automatically discharges out a drain. The carbonic water production apparatus is combined with a portable foot bath.

Abstract: A system for concentrating gas, using the concentrated gas to pump liquid, and recycling the gas and liquid is disclosed. The system comprises a body of liquid, a down pipe in fluid communication with the body of liquid, a gas injection apparatus for introducing gas into the liquid that passes through the down pipe, a separator for separating compressed gas from the liquid, and a gas-liquid recycle loop. The down pipe and the gas injection apparatus are structured and arranged to compress the gas. The gas-liquid recycle loop comprises a compressed gas storage vessel containing the separated gas, a reservoir containing liquid separated from the compressed gas, and a gas-liquid pump. The gas-liquid pump has a gas inlet in communication with the gas storage vessel, and a fluid inlet in communication with the reservoir. The gas-liquid pump is structured and arranged for pumping the liquid back to the body of liquid and delivering the gas to the gas injection apparatus.

Abstract: A process for producing carbonated water having a high concentration, inexpensively and easily, involves using a static mixer having 20 to 100 elements so as to provide a value Re×N of 100,000 to 2,000,000, in with Re represents a Reynolds number, when a mixture of water and carbonic acid gas flow in the static mixer.

Abstract: A water curtain is provided which includes a drape assembly having a drape hood, material drape, float overflow shut-off, collection return, a drainage line solenoid which preferably is electric, a drainage line, a filter, drape solenoid which preferably is electric, a drape feed line, a pump, a pump power line, an on/off switch to a power source which preferably is a ground fault circuit interrupter (GFCI) power line for obvious safety concerns, a feed line, and a shutoff valve. The water supply may be electrically controlled by solenoid valves and has a float overflow shutoff control in some embodiments.

Abstract: Hot water (12) in a bath (11) is pumped up by a suction pump (9) and introduced into a carbon dioxide gas dissolver (7) through solution flow rate adjusting means (14) and then, poured into the bath (11). Carbon dioxide gas supplied from a carbon dioxide gas cylinder (1) is introduced into the carbon dioxide gas dissolver (7) through gas flow rate adjusting means (5). At this time, the quantity of bubbles existing in artificial carbonated spring in a take-out pipe (15) is measured with a measuring device (13), and the solution flow rate adjusting means (14), gas flow rate adjusting means (5) and the like are controlled by means of a control device (16) using a relational expression between a preliminarily set quantity of bubbles and carbon dioxide concentration to obtain a desired concentration of carbon dioxide gas in carbonated spring.

Abstract: A system for aerating liquid within a liquid retention structure including a liquid delivery tube in fluid communication with a gas exchange chamber and a pump. The gas exchange chamber includes an air inlet and a gas outlet. The pump is configured to pump liquid within the liquid retention structure through the liquid delivery tube and into the gas exchange chamber so that harmful gases contained within the liquid escape from the liquid and exit through the gas outlet. Fresh air enters into the gas exchange chamber through the air inlet and is absorbed into the liquid within the gas exchange chamber.

Abstract: A device for stirring and aerating a liquid in a treatment vessel may include a funnel disposed in the upper portion of the vessel to form a passage with the vessel. A duct is connected to the funnel and extends toward the bottom of the vessel and includes an opening in each of its upper and lower portions. A main screw is situated in the duct and has a driving device for driving its rotation. Also, the stirring device may include an aerating device that incorporates air into the liquid by imparting movement to the liquid inside the stirring device so that the liquid cascades over an upper edge and a peripheral structure disposed in the vicinity of the upper edge of the funnel.

Abstract: A carbonic water production apparatus equipped with a carbonic acid gas dissolving apparatus 3 and a circulation pump 1 wherein water in a bath 11 is circulated by the circulation pump 1, and a carbonic acid gas is fed into the carbonic acid gas dissolving apparatus 3 to dissolve the carbonic acid gas in the water, and wherein the circulation pump 1 is a positive-displacement metering pump having a self-priming ability; a carbonic water production method using this apparatus; a carbonic water production method comprising an early step for producing a carbonic water and a concentration maintaining step for the carbonic water; a carbonic water production apparatus equipped with a control for controlling the feeding pressure of carbonic water gas so that give an intended concentration of carbonic acid gas; a carbonic water production apparatus which automatically discharges out a drain; and a carbonic water production apparatus combined with a portable foot bath.